Four types of experiments are proposed to investigate hemispheric specialization in rhesus monkeys. Three of them use stimuli or procedures known to reveal lateralization in man; the fourth explores whether two more naturalistic behaviors reveal hemispheric asymmetries. All the experiments compare learning or performance of the two hemispheres of split-brain monkeys. The first experiment tests learning and generalization of discriminations based on facial expression, a right hemispheric ability in man. The second investigates the ability of each hemisphere to perceive and reproduce the sequential order of events, a left hemispheric ability in man. The third examines a task involving auditory - visual comparisons that is reported to be lateralized in monkeys. The same task allows study in monkeys of the exaggerated suppression of input from the ipsilateral ear found in dichotic listening experiments with split-brain patients. Finally, the preferences of the two hemispheres for viewing slides and video tapes of interesting stimuli and the behavioral reactions to these stimuli will be observed.